Solving the questions from the 2018 Chemistry exam
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Please, experts, take a look and tell me how to solve this problem
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For the original operating conditions, the overall heat transfer coefficient K = 833.33, and the logarithmic mean temperature difference △tm = 54.85°C. Under the new operating conditions, since the flow rate is twice as high, the heat transfer coefficient α’ = 2^(0.8)α = 1741; thus, the overall heat transfer coefficient K’ = 1291.4. The basic equation for heat transfer is: Q = KA△tm = q1·CP1(T1–T2) = q2·Cp2(T2–T1). Substitute the values: Equation 1: q2·Cp2(40–30) = 833.33·A·54.85. Equation 2: 2q2·Cp2(t’–30) = 1291.4·A·△t’m’. By dividing Equation 1 by Equation 2, only one unknown remains, namely t’; the value of t’ is 37.9℃
The question mark means multiplication; it didn’t get typed in